Walking vehicle

ABSTRACT

A walking vehicle is provided which comprises a main body having four corners, four leg mechanisms, one connected to each of the corners, a driving means for driving the leg mechanisms and a control means for controlling the driving of the leg mechanisms.

United States Patent 1191 Ikeda et al. Nov. 26, 1974 WALKING VEHICLE2,918,738 12 1959 Barr 180 8 E x 1 1 Kiichi Ikeda; Kimam Taguchi;5333333 1371321 #2253 13?" 11111238111121 Taketoshl Nolaki; Shuntets"3,134,453 5 1964 Cirami 180 8 E Mats m a of y ap 3,135,345 6/1964Scruggs 180/8 E [73] Assignee: Agency of lndustrial Science &

Technology, kyo, Japan FOREIGN PATENTS OR APPLICATIONS 423,063 12 1925Germany 180/8 E [22] Flledl 1973 627,988 11/1961 Italy 180 8 E [21]Appl. No.: 346,321

' Primary Examiner-Leo Friaglia 30 Foreign Application Priority DataAttorney Agent Firm-Kurt Kelman May 30, 1972 Japan 753731 A 27, 1972 J47-50043 pr 57 ABSTRACT A walking Vehicle is provided which Comprises amain [58] i 280/1 181 body having four corners, four leg mechanisms, one0 care connected to each of the corners, a driving means for driving theleg mechanisms and a control means for [56] References C'ted controllingthe driving of the leg mechanisms.

UNITED STATES PATENTS 1,511,928 10 1924 Zboril 180 8 E 4 Claims, 36Drawing Figures WALKING VEHICLE BACKGROUND OF THE INVENTION The presentinvention relates to a control system for a walking vehicle providedwith four legs.

A walking vehicle with four legs has the following advantages overconventional vehicles using wheels, such as automobiles, rail-way cars,etc.:

It is possible to move along rough surfaces such as unpaved roads androcky areas, etc., or steep surfaces such as mountain passages andslopes, etc.

It is also possible to move along surfaces such as marshes, deserts andicy and snowy lands, etc, whose physical properties such as supportingcapacity, firmness and coefficient of friction, etc., are unstable.

Changes in direction and velocity can be easily performed.

Since, as above mentioned, the four-legged walking vehicle hasadvantages over the conventional vehicle using wheels in that thewalking vehicle can move on and along all types of surfaces, it iscapable of being utilized widely not only in the exploitation of thebottom of sea and the surfaces of heavenly bodies but also in rescueoperations, high altitude and fire-extinguishing work, and other jobstoo difficult for men to do directly.

Despite the above-mentioned advantages of the fourlegged walkingvehicle, such vehicles have not come into generally use because of thecomplex construction thereof.

An object of the present invention is to provide a four-legged walkingvehicle which has a simple construction and is able to perform variouswalking functions.

SUMMARY OF THE INVENTION In order to achieve the above mentioned objectof the present invention, the four-legged walking vehicle according tothe present invention is provided with a means for appropriatelycontrolling the operation of the leg mechanisms secured movably to thecorners of the main body of the walking vehicle so that the four legsare driven appropriately to walk the vehicle in complex patternsincluding forward walking, reverse walking and turn about.

Other objects and features of the present invention will become apparentfrom reading the detailed explanations of embodiments of the presentinvention with reference to the drawings, in which:

FIG. I is a side view of an embodiment of a fourlegged walking vehicleaccording to the present invention;

FIG. 2 is a bottom view of the embodiment shown in FIG. 1;

FIG. 3 is a side view of a portion of the embodiment in FIG. 1, showinga walking cycle comprising walking and return strokes of one legmechanism;

FIGS. 4(a) to 4(e) are explanatory illustrations for showing one walkingcycle with attitude variation when the four legs are driven out of phasefrom each other by 90;

FIGS. 5(a) to 5(d) are explanatory illustrations showing one walkingcycle when the front leg mechanisms and the rear leg mechanisms areseparately driven in phase while a phase difference of 180 existsbetween the front legs and the rear legs;

FIGS. 6(a) to 6(d) are explanatory illustrations showing one walkingcycle when the front and rear legs on either side are in phase while thelegs on one side are 180 out of phase from those on the other side;

FIGS. 7(a) to 7(d) show the attitude variation during one walking cycleaccording to FIGS. 6(a) to 6(a);

FIG. 8 shows the walking mode of the main body as it turns to the left;

FIGS. 9(a) to 9(d) show one walking cycle in the mode shown in FIG. 8;

FIG. 10 is a side view of another leg mechanism;

FIGS. 11(a) to 11(e) show the legs in the state of quick return;

FIG. 12 is a schematic illustration of one mechanism for providing quickreturn stroke;

FIG. 13 is another example of a mechanism for providing quick returnstroke;

FIG. 14 is another example of a leg mechanism;

FIG. 15 is another example of a leg mechanism which is a modification ofthat shown in FIG. 10 and FIG. 16 is a further example of a legmechanism.

Generally, the present four-legged walking vehicle comprises a mainbody, four leg mechanisms, one provided at each of four corners of themain body, for supporting and driving the main body, a driving means fordriving the leg mechanisms and a control means for controlling themotions of the respective leg mechanisms.

FIGS. I and 2 show an embodiment of the walking vehicle, in which eachof the legs 2 connected rotatably to the corners of the rectangular mainbody I comprises upper two linkages 4 each of which has an elongatedslot 11 and lower two linkages 5. The upper linkages are connectedrotatably at their upper ends to the main body I and are crossed to forma generally X- shape. The lower linkages 5 are rotatably connected witheach other at their lower ends and are adopted to contact with a roadsurface. The upper end of each lower linkage 5 is connected rotatably tothe lower end of an upper linkage 4.

At the center of the main body, there is mounted a motor 3 for drivingthe respective leg mechanisms so that the center of gravity center ofthe motor coincides with the center of gravity of the main body. Therotational output of the motor is transmitted equally to the front legsand the rear legs through a driving shaft 7 for the front legs and adriving shaft 8 for the rear legs and through suitable gear mechanisms6. At the opposite ends of the respective driving shafts 7 and 8, arefixed arms 9 provided with outwardly extending eccentric pins 10. Eachof the pins 10 is inserted into the slots 11 of the upper linkages 4 toform the crossing center of the two linkages 4, so that, upon therotation of the driving shaft 7 (or 8), the pin 10 provided on theassociated arm 9 is rotated around the shaft and reciprocates the twolinkages 4 through their slots 11 to thereby alternatively expand andcontract the lower end connection of the lower linkages 5 through alocus such as shown in FIG. 3. That is, assume that the main body 1 isfixed and the eccentric pin is rotated. When the pin is at the uppermostposition, the associated leg is in the contracted state and the lowerend connection of the lower linkages is at position A. If the pin isthen rotated through an angle of the end connection is transferred toposition B. When the pin is rotated through another 90, the leg is fullyexpanded and the connection reaches position C. When the pin is furtherrotated by 90, the position of the connection is moved to position D. Inthis manner, the lower end connection of the leg mechanism is expandedand contracted by the revolution of the arm 9 to complete one walkingcycle for the leg.

The main body 1 can be made to perform various walking functions bychanging the phase relationships between the legs.

Firstly, it is assumed that the positions of the eccentric pins 10associated with the opposite ends of the driving shaft 7 and of the pins10 associated with the driving shaft 8 are out of phase by 180 and arefixed so that the front left leg I and the rear right leg IV are inphase and also the front right leg II and the rear left leg III are inphase. Thus, the eccentric pins at diagonal opposite positions of themain body are in phase. FIGS. 4(a) 4(0) show the walking mode of themain body 1 due to the motions of the respective lower end connectionsof the legs. In the same figure, the symbol@ represents a leg whose endconnection is in contact with the ground, symbol C shows a leg whose endconnection is lifted above the ground, the arrows show the direction ofmotion of the legs, symbols A, B, C and D show the positions of the endconnections of the legs in terms of the locus shown in FIG 3 and G isthe position of the center of gravity of the total weight.

It is assumed that firstly all of the legs are in contact with theground as in FIG. 4(a) and walking is started from this state. In thisstate, the front left leg I and rear right leg IV are at position D andthe front right leg II and the rear left leg III are at position B, sothat the attitude of the main body is maintained substantiallyhorizontal by these four legs.

When the respective legs start to move in the arrow directions upon therotation of the motor 3, legs I and IV are moved forwardly as theirlengths expand and, since the G of the whole falls slightly off animaginary line drawn between the legs [I and III (See FIGI 4(b)), thelegs II, III and IV are grounded and support the weight of the mainbody. However, the major part of the total weight is supported by thelegs 11 and III. Accordingly, since the friction between the groundsurface and these two legs II and III which support the substantial partof the weight becomes larger than that between the surface and the legIV bearing a relatively small weight, the end connection of the legs IIand III become fulcrums which do not move with respect to the surfacebut cause the main body itself to move, while the leg IV slips along thesurface, resulting in the movement of the main body in the directionopposite to the moving directions of the legs II and III. That is, themain body moves forward.

Since the legs II and III continue to expand until the end connectionsthereof reach the midway point of their strokes, i.e., reach theposition D on the locus in FIG. 3 and the legs I and IV continue tocontract until their end connections reach the position A, the main bodyis raised at the legs II and III and lowered at the leg IV, resulting inan inclination of the main body such that the leg 1 is liftedconsiderably from the ground surface as shown in FIG. 4(c).

Although the main body continues its forward movement even afterreaching the state shown in FIG. 4(0), the leg IV will be lifted fromthe ground surface because the diagonal line drawn between the legs IIand III is shifted behind G and the leg I is put in contact with thesurface through an intennediate transition state in which the main bodyis supported by two legs, as shown in FIG. 4(c). Accordingly the body issupported by the legs I, II and III. In the last state, the attitude ofthe body is remarkably changed to one wherein the front left portionthereof is lowered.

Since, after intermediate stroke position of the legs shown in FIG.4(0), the contracted legs I and IV begin to expand and the expanded legsII and III to contract, the tilted main body begins to recover itshorizontal attitude. Since, even in this state, the substantial part ofthe total weight is still supported by the legs II and III, the frictionbetween them and the surface are still larger than that between thesurface and the leg I. Therefore the main body continues its forwardmovement with the legs II and III as fulcrums while the leg I slipsalong the surface. (See FIG. 4(d)) When the respective legs continue tomove and reach position B or D, the lengths of the respective legsbecome the same and the weight is equally supported by the four legs sothat the horizontal attitude of the body is recovered. (FIG. 4(e))Thereafter the main body returns from the state shown in FIG. 4(e) tothe initial state shown in FIG. 4(a), through a sequence similar to thesequence from FIG. 4(a) to 4(e) but with the moving modes of the rightand left legs reversed, completing a full walking cycle.

In this manner, by making the two legs on either side out of phase legand the diagonally opposite legs in phase, the main body can be made tomove forward, alternatively rocking with the diagonal lines as axes.

FIGS. 5(a) to 5(b) show the movement of the main body in the case wherethe pair of front legs I and II are in phase and the pair of rear legsIII and IV are also in phase but the phase of the front legs differsfrom the phase of the rear legs by 180. In this case, if the frictionalforces of the end connections of the respective legs with respect to theground surface are substantially the same, all end connections of thefour legs slip with respect to the surface and thus the main body doesnot move forward but swings at a fixed position. However, since actuallythere may be differences in friction of force with respect to thesurface between the ends of the front legs and the rear legs due to therespective motions of the legs and the displacements of the endsthereof, the main body can move forwardly. When the front leg I is inthe most extended condition, the rear leg III is in the most contractedstate. (See FIG. 5(a)) Since the position of the center of gravity G ofthe main body in this state is shifted slightly to the rear leg side,the contact point between the rear legs and the surface is not shiftedeven when the motion of the front and rear legs is commenced, so thatthe front legs slip along the surface and the main body advances asshown in FIG. 5(b). When the motion of the legs further continues andthe main body begins to tilt forward, the position of G is shiftedforward to the front leg side and the weight supported by the front legsincreases while that supported by the rear legs decreases. Accordinglythe friction forces of the front legs become larger and the rear legsslip, resulting in the forward movement of the main body through thestate in FIG. 5(0) to the state shown in FIG. 5(d). Thereafter, the mainbody takes the attitude shown in FIG. 5(a) again with the front legsslipping and repeats the same cycles, resulting in a con tinuous walkingmovement.

In this manner, by making the front legs and the rear legs in phaserespectively and making the front legs out of phase with respect to therear legs by 71', the main body can advance while tilting to and fro.

FIGS. 6(a) to 6(d) show a case where the front and the rear left legs Iand III and the front and rear right legs II and IV are in phase,respectively, and the left leg or legs are out of phase with respect tothe right leg or legs by 180. In this case, if the respective legs havesubstantially the same friction with respect to the ground surface, themain body will merely slip and cannot advance. However, since G isshifted to and fro with the extending and contracting motions thereof,the main body can advance accordingly. FIG. 6 shows the positions of theleg points in the various states and FIG. 7 shows the attitudes of themain body corresponding to such positions of the leg points.

As shown in these figures, when the left legs I and III are in the mostextended state and the right legs II and IV are in the most contractedstate, G is closer to the right leg side. (FIGS. 6(a) and 7(a))Accordingly the friction of the right legs becomes larger than that ofthe left legs and thus, even when the respective legs move, the contactpoints between the right legs and the ground surface do not shift andthe left legs slip over the surface, resulting in the forward movementof the main body as shown in FIG. 6(b). Upon further motion of the legs,the left legs are contracted, tilting the main body leftwardly and thusshifting G to the left leg side (FIGS. 6(0) and 7(a)). Accordingly, thefriction force of the left legs increases and consequently, even whenthe respective legs further move, the contact points of the left legsare not shifted and the right legs slip with respect to the surface,resulting in a further advancement of the main body as shown in FIG.6(d). The main body then recovers the initial state shown in FIG. 6(a)upon the slipping of the left legs thereof and thus repeats itsadvancement in the same manner.

In this way, by making the left side and right side legs in phase,respectively, and making the left out of phase with the right by 180,the main body can move forwardly, alternately tilting to the right andleft.

The description given above has been made for linear advancement of themain body. In any of the above cases, the walking efficiency is bestwhen the phase difference is 180. However, the. main body can walk evenwhen the phase difference is slightly varied from 180. In this case,however, the walking efficiency will be lowered slightly.

Now, non-linear motion of the main body will be described with referenceto FIG. 8. That is, the turning mode will be explained.

As in the cases previously mentioned, when a pair of legs positioneddiagonally which support the substantial part of the weight are inphase, the main body moves linearly. However, when the strokes of suchtwo legs aremade different from each other during any time intervalwithin their strokes, the main body can move non-linearly, that is, itcan turn.

As shown in FIG. 8, assuming that the end connections of the two legs IIand III are at positions Y and W, respectively, at a time t and the twolegs make different strokes in direction and velocity so that these legsreach positions F and E, respectively, at a time At after the time t,the main body will move in the direction opposite to the arrows,resulting in a leftward turning by an angle 0.

During this turning movement, since the friction of the one of the twofulcrum legs II and III which supports the larger part of the weightbecomes largest, the end connection of this leg will not be shiftedrelative to the surface and thus the other fulcrum leg will move withrespect to the surface.

Accordingly, if the weight supported by the leg III at the position W islarger than that supported by the leg II at the position Y, the mainbody will be moved to a position defined by the leg positions W, X, Yand Z, while the leg II which was initially at the position Y slips onthe surface and reaches the position F. As a result, the main body turnsto the left, while moving slightly backward. On the other hand, althoughthere is always one leg other than the fulcrum legs which is in returnstroke and in contact with the surface, the friction thereof withrespect to the surface is relatively small and accordingly the effect ofsuch small friction can be ignored.

In such movement of the main body, the turning angle 6 0f the main bodycan be expressed as follows:

when

0 4% I 0, left turn,

6 be 0 right turn 9 #0 0 linear movement The traveling distance I of themain body can be expressed as follow:

As described above, in order to make the movement of the walking Vehiclenon-linear, the strokes of the two fulcrum legs should be made differentfrom each other for a suitable time interval of their walking and returnstrokes so that the vehicle turns or snakes because of the difference ofthe strokes. Changing the stroke or making the strokes different can beperformed by varying the vertical position of the driving shaft 7 (or 8)in FIG. I or by changing the mounting position of the upper linkagethereof with respect to the body.

As a concrete example of the above described moving mode, an embodimentis shown in FIG. 9 in which such non-linear movement is achieved bydisplacing the phase of one leg from the phases of the remaining threelegs.

In FIG. 9, legs I, III and IV are made in phase and only the leg [I isout of phase by with the other three legs (FIG. 9(a)). Since theextensions of the strokes of the legs II and III which are fulcrum legsare the same but in opposite directions, the vehicle moves backwardslightly while turning left (FIG. 9b)). At this time, the front rightleg II extended and the remaining legs are contracted. With furthermotion of the legs, the vehicle turns to the left and the attitudethereof becomes horizontal (FIG. 9(c)). Thereafter, the fulcrums aretransferred to the legs I and IV and the vehicle moves straight becausethe moving directions and the strokes of the legs I and IV are the same,respectively (see FIG. 9(d)).

In the embodiments heretofore described, the phase of one or two legs ismade different from other legs by 180.

Another example will now be described, in which, by making therespective legs different in phase or position from each other by asuitable angle, the main body can reach a destination while makingcomplex movement. As a method of regulating the respective phases, it ispossible to set them at any desirable position by providing anelectro-magnetic clutch between the driving shaft 7 (or 8) and theassociated arm 9 and applying an electrical signal to the clutch.

In the previous embodiments, although each of the legs mounted on thefour corners of the main body 1 comprises two crossed upper linkages 4and the two lower linkages connected rotatably to the upper linkages andis driven by a common motor 3, this construction is not critical and anyother constructions may be utilized so long as it provides the vehiclewith the same functions. For example, as shown in FIG. 10, a legmechanism may be used in which a rod 12 is mounted rotatably on the mainbody 1, one end of which is connected to a rod of a piston 31 and theother end of which is connected to a walking arm 13 and the arm 13 whichhas a lower end in contacting with the surface and supports the mainbody is connected through a support arm 14 to the main body.

On such leg is mounted to each corner of the main body and driven by apiston to reciprocate each arm 13. In this case, by appropriatelyregulating the times at which fluid pressure is applied to each pistoncylinder, the respective-legs will move reciprocally with any desiredphase differences, so that the main body readily moves straight orsnakes.

In the walking movement of the vehicle provided with four legs, the bodyis usually supported by three of the legs. However, when the three legshave the same walking and return strokes, one of the three legs mustslip on the surface in the direction of movement of the vehicle. Thisslipping leg may be obstructive to the stability of walking and, forexample, when the slipping leg encounters some protrusion or recess onthe road surface and is caught thereby, the direction of the vehicletends to be changed or the walking movement itself may be stopped.

In order to eliminate such slippage of the leg and ensure stable walkingthe legs other than the legs which, at that time, are in contact withthe surface must be returned quickly and replaced on the surface at aforward position, all before the center of gravity has had time to shiftoutside the triangle defined by the three lines connecting the legssupporting the weight.

Assuming that the end point of each of the legs performs a walkingmotion, the cycle time of which is 2z, one walking stroke S of the legsupporting the weight corresponds to a half cycle, that is, 2.Accordingly, when the phase difference between the adjacent legssupporting the weight of approximately z/3, the gravity center must bewithin the triangle. Furthermore, it is necessary to lift the leg otherthan the three and bring it forward by strokes S while the three legsare moving by approximately z/3, respectively. Accordingly, the movingvelocity of the leg in the return stroke should be about three times thevelocity in the walking stroke.

The above relation will be described arithmetically with reference toFIG. 11.

FIG. 11(a) to 11(2) showthe phase relations of the four legs at the timethe legs are in contact with the surface during one walking cycle.

When the legs I, II, III and IV are in the state shown in FIG. 11(a),the legs 11, IV and I move backwardly by 8A, 6B and 8D, respectively forthe first time interval z/3 to move the main body forward.

While the leg III is quickly moved forward by 80,, as shown in FIG.11(b). During the next z/3, the legs II, IV and III move backward by 6A6B 6C respectively while the leg I moves forward by 8D,, as shown inFIG. 11(0) and thus the respective legs move backward and forward,alternatively.

As will be seen from FIG. 11(e), the travel distances of the respectivelegs have the following relations.

Taking the average of the traveling distances for every z/3 as 5 andSA4=SB3=SC1:SD2=S S can be expressed as Equation (4) differentiated bytime is as follows ds/dl=V =3V5 (5) That is, the mean shifting velocityV of the leg in the return stroke must be three times the mean shiftingvelocity V8 of the leg in the walking stroke. However, in the returnstroke, since the leg is lifted and then returned, the velocity V mustbe larger than three times the velocity S8.

As a mechanism for quickly returning the leg in the return stroke, anyof various quick return mechanisms may be used. Examples of suchmechanisms are shown in FIGS. 12 and 13 respectively.

The mechanism shown in FIG. l2,comprises spur gears 15 and 18 mounted onthe shaft 7 (or 8) rotated by a suitable driving means, and fractionalspur gears 17 and 19 mounted on a shaft 16. The gear 15 meshes with thegear 17 and, when the gear 15 is disengaged from the gear 17 after theshaft 16 is rotated fora predetermined fraction of one revolution, thegear 18 on the shaft 7 which has a larger size than that of the gear 15and the gear 19 which has a smaller size than that of the gear 17 meshwith each other to thereby rotate the shaft 16 at a higher speed for theremaining cycle than that established by the meshing of the gears 15 and17, so that the leg can be quickly driven for a particular time by theeccentric pin 10 on the arm 9 mounted on the shaft 16. On the otherhand, in order to partially vary the speed of a leg in the walkingstroke, it may be possible to provide a suitable number of fractionalspur gears, which are similar to the gear 17 but have different sizes,on the shaft 16 and a corresponding number of spur gears havingdifferent sizes accordingly and meshing with the additional fractionalgears for different angles so that the rotation of the shaft 7 can betransmitted to the shaft 16 at any desirable ratios for different timeintervals.

In another mechanism shown in FIG. 13, a spur gear 20 mounted on thedriving shaft 7 (or 8) rotated by a suitable driving means meshes with afractional spur gear 21 mounted on the shaft 16. The gear 21 is biasedby a spring 22 in the clockwise direction. Upon the rotation of the gear20 in the anticlockwise direction, the gear 21 is rotated clockwise and,after a predetermined fraction of one revolution is completed and thegear 21 is disengaged from the gear 20. It is quickly brought intoreengagement with the gear 20 by the effect of the spring 22, to therebymove the leg driven by the eccentric pin quickly for a particular timeinterval.

In the leg mechanism shown in FIG. 10 which utilizes the reciprocalmotion of a piston as its power source, the walking stroke and thereturn stroke of the leg can be desirably made slow and quick by makingthe feeding and exhausting velocities of the working fluid into and fromthe piston cylinder slow and quick.

Furthermore, the leg can be constructed as shown in FIG. 14 in which oneend of a walking arm 23 having a rectangular slot 23 and an upper end ofan auxiliary arm 24 having an elongated slot 24 and secured rotatably tothe body 1 by pin 24a are rotatably jointed by a pin 28. A pin 27 fixedon a disk 25 is connected to and driven by the driving shaft 7 which isinserted into the slot 24. A pin 26 fixed to gear box 6 of body 1 onopposite side of the disk 25 is inserted into the slot 23' respectivelyso that by the rotation of the disk 25 the walking stroke and the returnstroke are made slowly and quickly respectively.

The mechanism shown in FIG. is similar to that shown in FIG. 10 but,instead of the auxiliary arm 14, a second piston 29 is provided, so thatthe arm 13 is contracted in the return stroke by exhausting the fluidcontained in the piston cylinder. In this manner, since the secondpiston 29 lifts and quickly returns the leg in the return stroke, thereturn motion itself becomes easy and there is no slippage of the leg.

The mechanism which is shown in FIG. 16 is a modification of that shownin FIG. 15. The piston 31 is used to reciprocate the walking arm 13 andthe piston 29 when actuated in the return stroke lifts the leg so thatthe slippage of the leg is eliminated.

The mechanisms described heretofore are mere examples of mechanismsusing eccentric gears, cam mechanisms and/or crank mechanisms which maybe used herein.

In these mechanisms, the phase controls and the speed control inreciprocal motion of the respective legs may be performed manually or byan electronic computer.

As will be clear from the foregoing description, in the presentfour-legged walking vehicle, the construction of each leg is simple, andthe phase control of the respective legs is easily performed. And thevehicle itself can walk in various modes. Furthermore, the presentwalking vehicle can be used for various purposes by regulating thephases and speeds of the respective legs. It can also be used foreducation purposes such as simulation of the various walking modes ofanimal, experiments and analysis thereof, etc. Furthermore, since thepresent walking vehicle can be made to move in unique and fantasticmodes by changing the attitude thereof, it can be used for toys, etc.

What we claim is:

1. A walking vehicle which comprises in combination, a main body, fourleg mechanisms, one of said four leg mechanisms disposed at each of fouredge locations of the main body for supporting and driving the mainbody, each of said leg mechanisms having two upper linkages each havingan elongated slot disposed along its body, and two lower linkagesmovably joined at one end, said upper linkages connected rotatably attheir upper ends to the main body at their lower ends one eachrespectively to a lower linkage, said upper linkages crossed to form agenerally X-shape, a rotating member disposed at each leg mechanism andhaving an eccentric pin disposed thereon, said pin projecting each ofthe elongated slots of the upper linkages, and means for rotating eachrotating member relative each other such that one leg mechanism isrotated about out of phase relative to an adjacent leg mechanism wherebywalking movement of the vehicle is effected.

2. The walking vehicle of claim I wherein each rotating member isprovided with a means for quickly returning from a non-ground contactingposition to an extended ground contacting position.

3. The walking vehicle of claim 2 wherein the means for quicklyreturning comprises a first relatively small spur gear and a secondrelatively large spur gear disposed along a first rotating drivingmeans, a first relatively large fractional spur gear disposed to meshrelative said first spur gear and a second relatively small fractionalspur gear disposed to mesh relative the said second spur gear, saidfractional spur gears disposed along a second rotating driving meansconnecting to one of said rotating members, said first spur gear andsaid first fractional spur gear being in mesh relationship when said legis in retracted non-ground contact, said second spur gear and secondfractional spur gear being in mesh relationship when said leg is inground contact position.

4. The walking vehicle of claim 2 wherein the means for quicklyreturning comprises a spur gear mounted on a driving shaft, a fractionalspur gear mounted on a shaft disposed to one of said rotating members,said spur gear positioned for mesh contact with the fractional spurgear, and a spring member disposed for returning the fractional spurgear from non-meshing position to re-engagement with said spur gear.

1. A walking vehicle which comprises in combination, a main body, fourleg mechanisms, one of said four leg mechanisms disposed at each of fouredge locations of the main body for supporting and driving the mainbody, each of said leg mechanisms having two upper linkages each havingan elongated slot disposed along its body, and two lower linkagesmovably joined at one end, said upper linkages connected rotatably attheir upper ends to the main body at their lower ends one eachrespectively to a lower linkage, said upper linkages crossed to form agenerally Xshape, a rotating member disposed at each leg mechanism andhaving an eccentric pin disposed thereon, said pin projecting each ofthe elongated slots of the upper linkages, and means for rotating eachrotating member relative each other such that one leg mechanism isrotated about 180* out of phase relative to an adjacent leg mechanismwhereby walking movement of the vehicle is effected.
 2. The walkingvehicle of claim 1 wherein each rotating member is provided with a meansfor quickly returning from a non-ground contacting position to anextended ground contacting position.
 3. The walking vehicle of claim 2wherein the means for quickly returning comprises a first relativelysmall spur gear and a second relatively large spur gear disposed along afirst rotating driving means, a first relatively large fractional spurgear disposed to mesh relative said first spur gear and a secondrelatively small fractional spur gear disposed to mesh relative the saidsecond spur gear, said fractional spur gears disposed along a secondrotating driving means connecting to one of said rotating members, saidfirst spur gear and said first fractional spur gear being in meshrelationship when said leg is in retracted non-ground contact, saidsecond spur gear and second fractional spur gear being in meshrelationship when said leg is in ground contact position.
 4. The walkingvehicle of claim 2 wherein the means for quickly returning comprises aspur gear mounted on a driving shaft, a fractional spur gear mounted ona shaft disposed to one of said rotating members, said spur gearpositioned for mesh contact with the fractional spur gear, and a springmember disposed for returning the fractional spur gear from non-meshingposition to re-engagement with said spur gear.